Eosinophilic granulomatosis with polyangiitis and its association with montelukast: a case-based review.

The association between the use of certain medications (including sulfonamides, hydralazine, and procainamide) and the occurrence of drug-induced lupus or hepatitis is well established. More recently, cases of immune-related adverse events ranging from inflammatory polyarthritis to necrotizing myositis in patients taking checkpoint inhibitors have been reported. However, data linking drugs to systemic vasculitis are scarce and at times debatable. Propylthiouracil, hydralazine, and minocycline have been associated with rare cases of ANCA-associated syndromes, including life-threatening pulmonary-renal syndromes and systemic polyarteritis nodosa-like diseases. Eosinophilic granulomatosis with polyangiitis (EGPA) has been reported in patients taking leukotriene inhibitors. Since the link between the use of leukotriene inhibitors and occurrence of EGPA remains highly controversial, we performed a literature review for cases of EGPA in patients taking montelukast without prior history of oral corticosteroid use. We found 24 cases, along with our own two cases described, making 26 cases in total. The mean age was 43 and a majority (18/26) were female. In majority of cases EGPA-like disease never relapsed after they were taken off leukotriene inhibitors suggesting a clear causal relationship between the use of these drugs and occurrence of eosinophil-rich systemic EGPA.